The height of a cone is 15 cm. If its volume is 1570 cm3, find the radius of the base. (Use π = 3.14)
Given,
Height of the cone (h) = 15 cm
Let radius of base of cone be r cm.
Volume of cone = 1570 cm3
Substituting values we get :
∴13πr2h=1570⇒r2=1570×3πh⇒r2=1570×33.14×15⇒r2=471047.1⇒r2=100⇒r=100⇒r=10 cm.\therefore \dfrac{1}{3}πr^2h = 1570 \\[1em] \Rightarrow r^2 = \dfrac{1570 \times 3}{πh} \\[1em] \Rightarrow r^2 = \dfrac{1570 \times 3}{3.14 \times 15} \\[1em] \Rightarrow r^2 = \dfrac{4710}{47.1} \\[1em] \Rightarrow r^2 = 100 \\[1em] \Rightarrow r = \sqrt{100} \\[1em] \Rightarrow r = 10 \text{ cm}.∴31πr2h=1570⇒r2=πh1570×3⇒r2=3.14×151570×3⇒r2=47.14710⇒r2=100⇒r=100⇒r=10 cm.
Hence, radius of the base = 10 cm.
